Synthesis of pterocarpans through palladium-catalyzed oxyarylation of alkoxy-2H-chromenes with o-iodophenols

New 5-carba-pterocarpans: Synthesis and preliminary antiproliferative activity on a panel of human cancer cells

Natural pterocarpans and synthetic 5-carba-pterocarpans are isosteres in which the oxygen atom at position 5 in the pyran-ring of pterocarpans is replaced by a methylene group. These 5-carba-analogues were obtained in good yields through the palladium-catalyzed oxyarylation of alcoxy-1,2-dihydronaphthalens with o-iodophenols in PEG-400. They were evaluated on human cancer cell lineages derived respectively from prostate tumor (PC3, IC₅₀ = 11.84 μmol L^-1, SI > 12)) and acute myeloid leukemia (HL-60, IC₅₀ = 8.81 μmol L^-1, SI > 16), highly incident cancer types presenting resistance against traditional chemotherapeutics. Compound 6c (LQB-492) was the most potent (IC₅₀ = 3.85 μmol L^-1, SI > 37) in SF-295 cell lineage (glioblastoma). Such findings suggest that 5-carba-pterocarpan can potentially be new hit compounds for further development of novel antiproliferative agents.